Heretofore, a rotary valve has been known which opens and closes a combustion chamber and intake and exhaust passages with a rotary member instead of valve members of a mushroom-valve type, which known type of valve is employed for the intake and exhaust valves in an internal combustion engine. The rotary valve of such known type results in a plethora of problems, as set forth hereinbelow.
One of the problems attendant such known valve relates to the cooling effect of a rotary valve and a housing thereof. In any conventional valve of this type, an intake passage of the valve proper and the opening thereof, and an exhaust passage and the opening thereof, are respectively separately provided. Taking into account the thermal expansion of, as well as the lubrication between, a housing and the rotary valve proper, the valve proper and a cylinder head forming the housing are cooled by means of water or oil. The sealing surfaces between the elements are also lubricated by means of oil. Consequently, the conventional means has attendant problems such as a complex construction, because it requires a pump for the cooling medium, a pump for the lubricating oil, pipes, members which form a lubricating portion, etc. Thus, the number of components is increased. Further, it is required that the conventional means be provided with means for cooling the lubricating oil.
Another one of the problems attendant the known valve construction relates to a sealing means. A technical difficulty exists in the sealing between opening portions of a valve proper and an opening portion of a combustion chamber. Further difficulties exist in sealing, sticking caused by heat, abrasion, etc., between the valve proper which rotates at a high speed, and the housing. If the sealing is a fixed one, the sticking caused by heat results from distortion of each part due to thermal expansion, and gas leakage is caused thereby. If the sealing is applied only between opening portions of the valve and the combustion chamber, there is a risk of gas leakage. In addition, the rotary valve causes various kinds of problems concerning sealing, for example, against oil leakage and oil entrance upon driving the valve.
The present invention provides a rotary valve structure which eliminates the foregoing problems and shortcomings attendant the conventional means.